Pseudomonas Canker of Kiwifruit. Dan C. Opgenorth, Plant Pathologists, California Department of Food and Agriculture, Sacramento 95814. M. Lai, Plant Pathologist, M. Sorrell and J. B. White, Agricultural Biological Technicians, California Department of Food and Agriculture, Sacramento 95814. Plant Dis. 67:1283-1284. Accepted for publication 22 July 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-1283.

A new disease of kiwifruit (Actinidia chinensis) has been observed in California. Symptoms appear in early spring as wilt and cane blight. Cane cankers with deeply shriveled and dried bark appear later. Internal canker tissue appears red-rusty brown. Cane cankers are usually found adjacent to pruning wounds. A fluorescent Pseudomonas sp. that produces a hypersensitive response on tobacco is commonly isolated from canker tissues. Further characterization has shown most Pseudomonas isolates to be positive for syringomycin production, potato rot, sucrose utilization, and levan production and negative for oxidase, arginine, and d(–)tartrate utilization. Inoculated peach and kiwifruit shoots have shown injuries similar to field symptoms when subjected to low temperatures. Koch’s postulates have been satisfied using seedling plants grafted to cultivar Chico-Hayward.